The present invention relates to an element for thermal insulation between two building parts, particularly between a building and a protruding exterior part, comprising an insulating body to be allocated between the two building parts and reinforcement elements in the form of at least rod-shaped tensile reinforcement elements, which in an installed state of the element extend essentially horizontally and extend perpendicular to an essentially horizontal extension of the insulating body through said body.
Various embodiments of elements for thermal insulation are known from prior art, which primarily serve to support building parts projecting from buildings, such as balcony plates, through a thermally insulating building joint. Here, the integrated reinforcement elements ensure the necessary transfer of the force and/or moment, while the insulating body is responsible to separate the two building parts from each other in a thermally insulating fashion while maintaining the joint.
In general, in relevant prior art tensile reinforcement elements are provided, usually produced from a rod-like material made from metal, which particularly in the proximity of the insulating body are made from stainless steel and in the area outside the insulating body are made from rebar. Stainless steel is used in the proximity of the insulating body and/or the building joint on the one hand due to its resistance to corrosion and on the other hand due to its poor thermal conductivity, and thus it is preferred over rebar in the proximity of the insulating body. However, rebar is commonly used in the area outside the insulating body, where neither resistance to corrosion nor thermal insulating features are relevant, since the rebar extends completely inside one of the two building parts.
Recently it has been attempted to further optimize the elements for thermal insulation, with it being tried to produce the tensile reinforcement elements, previously made almost exclusively from metal, now from a synthetic material, because it is considerably more cost effective than stainless steel and additionally it exhibits even lower thermal conductivity than stainless steel. An example for such an element for thermal insulation with tensile reinforcement elements made from a synthetic material is discernible from DE-U 20 2012 101 574. The tensile reinforcement elements called in this publication tensile release rods are made from fiberglass-reinforced synthetic, allowing two adjacent rods to be respectively connected to each other at their ends via a lateral plate, in order to yield a higher and more stable transfer of tensile forces. It is easily discernible from this type of anchoring of two tensile release rods via a lateral plate, that it is cumbersome and causes installation problems when connecting the reinforcement element, and that tensile reinforcement elements made from a synthetic are hard to anchor in the adjacent building parts particularly when, as in the described prior art, they are embodied with smooth walls and thus a type of end anchoring is required in the form of a lateral plate.
An alternative solution for the use of tensile reinforcement elements made from fiberglass or carbon fiber reinforced synthetic material is discernible from WO-A 2012/071596, in which the tensile reinforcement elements are made from closed loops, which based on their shape as a loop enter into a positive connection to an abutting building part and this way ensure the required anchoring. Looped tensile reinforcement elements have repeatedly been suggested in prior art; however due to their limited anchoring depth in the abutting building part and the here resulting low capacity to transfer strong tensile forces they exhibit considerable disadvantages, with the loop shape itself regularly resulting in a collision with the abutting reinforcement and thus leading to installation problems, similar to the above-described lateral plates.
These elements for thermal insulation with reinforcement elements made from a synthetic material were previously not convincing because their anchoring in the abutting building parts failed to attain the problems left unsolved in the past: Here, either the tensile reinforcement elements must generate via special geometries (e.g., by a loop form, lateral plates, and the like) a strong positive connection to the abutting building part, which in turn leads to installation problems due to the connecting reinforcement to be arranged in this area; or it must be attempted to provide the tensile reinforcement elements comprising a fiber-reinforced synthetic in the form of a tubular and/or rod material with a profiling and/or striation at their exterior, with here however the anchoring of these profiled tensile reinforcement elements made from a synthetic material in the abutting building part suffering the disadvantage that the fiber-reinforced synthetic on the one side and the concrete material of the abutting building part on the other side show generally such distinctly different temperature expansion coefficients that automatically different, temperature-related relative movements develop, which lead to tensions and/or expansions in the mutual contact area. This leads to destructions by either the profiling or the so-called concrete bases between the profiling shearing off. This results in the tensile reinforcement elements usually losing their ability to fulfil their function.
Another disadvantage of tensile reinforcement elements made from a synthetic material is the lack of subsequent bending property, compared to steel, which renders it necessary that the desired shape and length of the tensile reinforcement elements is already considered during the production of the rods. This leads to a considerably increased number of tensile reinforcement elements that need to be warehoused due to the accordingly high number of variants, which causes disadvantages with regards to logistics.